Jeet Kune Do is the Gung Fu style developed by the legendary Bruce Lee. Since Lee's death in July 20, 1973, much mystery has surrounded the system. While recovering from a serious back injury from weight training, he wrote his most famous work, the Tao of Jeet Kune Do. This brought attention to JKD, but told little of what the system techniques actually were. 
The history and definition of Jeet Kune Do (JKD) is the way of the Intercepting Fist. The name is demonstrated in many of the techniques such as blocking by striking or stop hit.
Lee took his primary training in the art and modified it to make it more effective in the real world. He eliminated many of the "traditional" elements and formalities to make the art more alive. The basis of JKD is Wing Chun Gung Fu. Lee was friends with the legendary boxer Muhammad Ali, and added some of Ali's techniques to the style to make the punches more devastating. To increase mobility in footwork, Lee added movement fundamentals from Fencing.
Most books on the work of Jeet Kune Do tell almost nothing of the original art, and some even leave the reader in a complete state of confusion. That is why Professor Hargrave wrote The Original Jeet Kune Do Training Manual ©. This manual gives the reader / practitioner a first-hand look at Lee's original techniques as taught in his private schools. 
When choosing your JKD you must understand that there are two separate versions of the art. The original JKD and the JKD concepts. One is no better than the other, but the original is the Lee method that he designed and taught, while the concepts brings many other arts or styles into play. Hargrave Martial Arts teaches the Original Jeet Kune Do. One of the first things you will notice when starting your JKD journey is that there are no uniforms and very little formality in the schools, and all combat artistss wear shoes. While little formality exists, respect is essential, and you must refer to your teacher with the proper title of Sifu (teacher).
There were three original JKD schools where Lee's art was taught. Los Angeles, Seattle, and Oakland. All three had different trademark techniques. The system taught by Hargrave is from the Oakland school with harmonious techniques from Los Angeles to create a more rounded original JKD experience.